Flexible fluid vessel and related methods

ABSTRACT

An apparatus for receiving a fluid is disclosed. The apparatus comprises an at least partially flexible vessel. The vessel includes a top wall and a plurality of sidewalls, a first of said sidewalls having a first length in a first plane that is greater than a second length of the second, generally orthogonal sidewall in the first plane, and a bottom wall depending from the at least two sidewalls. The vessel may have a generally rectangular cross section, and may include a depending portion. The vessel may be at least partially rigid. Related methods are also disclosed.

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/591,091, the disclosure of which is incorporated herein byreference.

TECHNICAL FIELD

This disclosure relates generally to the fluid handling arts and, moreparticularly, to a flexible fluid vessel and related methods.

BACKGROUND OF THE INVENTION

Modern fluid processing applications often employ disposable vessels forat least temporarily receiving and containing the fluid. For example, inthe course of bioprocessing, hermetically sealed bags formed of flexibleplastic film are often used for bulk intermediate storage, cell culturere-suspension, viral inactivation, final formulation, final fill, or asbioreactors. In any case, such vessels or bags generally come in twoshapes, cylindrical and cubical, typically have a flat bottom, anduniversally require some form of external support structure, such as arigid outer tank, during use.

When positioned in a tank and filled with fluid, flexible vessels thatare cylindrical or cubical have a tendency for improper seating, whichresults in separation from the sidewalls, and especially along thelowermost corners. An example of this tendency is illustrated in FIGS.1-3, which schematically depict a cubic bag B in an outer tank K. Asidefrom lacking aesthetic appeal, this separation results in gaps G andfolds F or creases in the flexible walls, which can not only impair theflow of fluid within the bag B and create crevasses where debris canbecome trapped, but also tend to stress the material and increase thechance of deleterious perforation. Such flat-bottomed vessels when usedwith a mixer M positioned along the floor (see FIG. 2) also generallyrequire a significant minimum amount of fluid to be present in order forthe mixer to become submerged prior to commencing the mixing operation.Draining the fluid from a flat-bottomed vessel may also pose an issue,since the flat floor does not in any way help to guide the fluid towarda stationary floor drain, regardless of its relative positioning.

Thus, a need is identified for a manner of providing an improvedflexible vessel, such as a mixing bag. The vessel would be capable ofuse in addressing a variety of different requirements for fluidprocessing operations, including the proper seating of the vessel in anyoutside tank or like support structure, mixing with less fluid thatwould be required with a flat-bottomed vessel, and improved draining ofthe fluid. The vessel would also be relatively easy to create andimplement. Overall, use of the improved vessel would thus lead to asimplification of the fluid processing and a concomitant reduction inthe expense associated with such use.

SUMMARY

According to one aspect of the disclosure, an apparatus for receiving afluid comprises an at least partially flexible vessel including a topwall and a plurality of sidewalls. A first of the sidewalls includes afirst length in a first plane that is greater than a second length ofthe second, generally orthogonal sidewall in the first plane, and abottom wall depending from the at least two sidewalls. The vessel maythus be rectangular in cross-section and, in particular, may have agenerally continuous rectangular cross-section from the top wall to thebottom wall. The area of the cross-section may instead generallydecrease continuously from a lowermost portion of the sidewalls to avertex of the bottom wall.

In one embodiment, the bottom wall of the vessel is flexible, but it maybe fully or partially rigid instead. In another embodiment, the bottomwall may comprise at least two generally triangular panels. In stillanother embodiment, the bottom wall may comprise at least two generallytrapezoidal panels. The bottom wall may also comprise at least fourgenerally triangular panels or at least four generally trapezoidalpanels.

The bottom wall may comprise a central region including a generally flatupper surface, which may be formed by a rigid portion. The rigid portionmay include at least one port. The rigid portion may be at leastpartially transparent.

The vessel may include a bottom weld for connecting at least part of thebottom wall to at least one of the sidewalls. The bottom weld may forman angle of less than 45 degrees relative to the sidewall in at least afolded state. The vessel may include a bottom K weld that is less than45 degrees, and a top K-weld that is 45 degrees or more. More generally,the vessel may include a top K weld having an angle that is greater thanthe angle of the bottom weld. The vessel in a folded position may alsoinclude a side comprising a first length of a bottom portion, anintermediate portion having a second length, and a third length of a topportion, wherein the first length is greater than the third length.

Another aspect of this disclosure pertains to an apparatus for receivinga fluid. The apparatus comprises an at least partially flexible vesselincluding an upper portion having a generally rectangular body and agenerally tapered portion depending therefrom.

Still a further aspect of this disclosure pertains to an apparatus forreceiving a fluid. The apparatus comprises a vessel having at least onesidewall and a bottom wall having a non-circular shape. The sidewall maybe flexible and the bottom wall may be rigid.

Yet another aspect of the disclosure pertains to an apparatus forreceiving a fluid, comprising a vessel having at least one flexiblesidewall and a rigid bottom wall having at least two generallytriangular panels. The bottom wall may include at least two generallytrapezoidal panels and possibly four generally triangular panels.

The disclosure also pertains to an apparatus for receiving a fluid,comprising a vessel having at least one flexible sidewall and a rigidbottom wall having at least four trapezoidal panels.

A further aspect of this disclosure is an apparatus for receiving afluid, comprising a bag having a bottom K weld that is less than 45degrees. The bottom K weld may be between about 40 and about 44 degrees.The bottom K weld may be about 41 degrees.

This disclosure also relates to an apparatus for receiving a fluid,comprising a vessel in the form of a bag having a top K weld with anangle, θ, and a bottom K weld with an angle, β, wherein θ>β.

Another aspect of the present disclosure pertains to an apparatus forreceiving a fluid, comprising a bag that in an inflated condition formsa generally rectangular structure, and in a folded condition includes aside having a dimension defined by a first portion T, a second portionB, and an intermediate portion I between the first and second portions,wherein T<B.

Any apparatus described herein may further include a support structurefor receiving the vessel. The support structure may comprise an interiormatching the contour of at least a lower portion of the vessel. Thevessel may further include a mixer, a sparger, a sensor, a drain, or anycombination of the foregoing.

Still a further aspect of the disclosure is an apparatus for holding afluid. The apparatus comprises a vessel including an at least partiallyflexible body having a depending portion comprising a plurality of firstpanels; and a support structure comprising a floor having a surfacecorresponding to each of the plurality of first panels.

This disclosure also has as one of any objects the provision of acollapsible mixing vessel including four generally planar and verticallyextending side panels and a sloped floor. At least two of the sidepanels may be generally rectangular, and at least one of the side panelsmay be generally square.

A collapsible mixing vessel comprising a flexible upper portionconnected to at least two sloping panels forming a floor also forms apart of this disclosure. The floor may be at least partially rigid.

This disclosure also pertains to processes, such as a method of forminga vessel for receiving a fluid. The method comprises forming a dependingportion of the vessel by connecting a first panel of film adapted toform a bottom of the vessel to a second panel of film also adapted toform the bottom of the vessel at an angle of less than 45 degrees.

Another aspect of the disclosure relates to a method of forming a vesselfor receiving a fluid, comprising connecting a plurality of panels offilm to provide the vessel with an upper portion comprising anon-circular body having a generally tapered depending portion.

A method of processing a fluid may comprise placing the disclosed vesselin a tank including a floor having a contour matching the shape of thebottom wall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are photographs illustrating one problem to be addressed bythe disclosure.

FIGS. 4-6 provide various views of fluid vessels according to thedisclosure.

FIGS. 7 and 8 illustrate further views of fluid vessels.

FIGS. 9-11 illustrate additional aspects of the disclosure.

DETAILED DESCRIPTION

Reference is now made to FIGS. 4-5, which illustrate a vessel 10 forreceiving a fluid, such as for processing. The vessel 10 includes abottom wall 12, a plurality of sidewalls 14, and a top wall 16. Thesestructures combine to form a generally rectangular body having a firstdimension, such as the length L, greater than a second, generallyorthogonal dimension, such as the width W, in a common plane, such as ahorizontal plane P coextensive with the lower terminus of the sidewalls14.

At least one of the components of the vessel 10 may be flexible, such asfor example the sidewalls 14. In one particularly preferred embodiment,all of the walls 12, 14, 16 are flexible. Thus, thus the vessel 10 takesthe form of a flexible bag (but for purposes of this disclosure, theterm bag may cover a vessel with one or more rigid walls or rigidportions as well). Consequently, the vessel 10 may collapse when notfilled with the fluid.

In accordance with one aspect of the disclosure, the bottom wall 12 ofthe vessel 10 is arranged to form a depending portion. For example, thebottom wall 12 may depend from the plane P and generally taper in adirection toward an axis extending through the center of the vessel butaway from the major plane of the corresponding sidewall 14.Consequently, the bottom wall 12 forms the depending portion generallyin the shape of a polyhedron (if the portion associated with plane Pwere a solid surface). In the illustrated embodiment, this polyhedron isgenerally an inverted pyramid, which includes four sides or panels, withtwo sides 12 a, and 12 b generally forming triangles, and two sides 12 cand 12 d generally forming trapezoids. The result at the interfacebetween the four ends of the panels 12 a-12 d is a seam 18 extending inthe longitudinal direction L, and defining a vertex essentially locatedat a central region 22 on the bottom of the vessel 10.

The presence of this seam 18 in the illustrated embodiment may dictatethat any port, such as for a drain, inlet, sensor, probe, or the like,should be provided at an offset or non-centered location along thesloping floor formed by the bottom wall 12. Thus, as shown in FIGS. 4and 5, one or more openings 20 may be provided on bottom side panel 12d, as well as on the opposite panel 12 c. As should be appreciated, theopening 20 when serving as a drain should be positioned as close to thevertex defined by seam 18 as possible, thus ensuring that the slopingpanels 12 a-12 d of the bottom wall 12 help to maximize the volume offluid that flows through the drain when emptying of the vessel 10 isdesired. Also, when a mixer M is present in the bottom portion of thevessel 10, including the sloping panels 12 a-12 d forming the bottomwall 12, it should be appreciated that a lesser volume of fluid isrequired to submerge the mixer, as contrasted with employing a vesselhaving a completely flat or planar bottom.

FIG. 5 shows an exemplary vessel 10 made according to the disclosure ina folded or flat condition, such as is usually the result just aftermanufacturing and prior to use (normally after inflation with a fluid).Fabrication of the vessel 10 generally requires securely connectingtogether multiple panels of film, such as by welding, adhesive, or thelike. The film panels are sized and shaped so as to provide theresulting vessel 10 with the generally rectangular shape incross-section when inflated.

In the preferred embodiment, the connection among the film panels ismade by welding, including along the portions of film that ultimatelyform the portions of the vessel 10 including the bottom wall 12 and thetop wall 16. These welds, typically referred to as “K welds” are placedsuch that they are at an angle, β, relative to an axis associated withthe longitudinal dimension of the sidewall 14, which angle is less than45 degrees (which may be considered a “K weld” of less than 45 degrees).In one particular embodiment, the angle is between 40-45 degrees, andmay be more specifically 41 degrees. The angles of the K welds on theopposite sides of the bottom of the folded vessel 10 may be equal orunequal, depending on the desired configuration.

Similar K welds may be provided for forming the top of the vessel 10.However, the angle, θ, of one or both of the top K welds may be greaterthan that of the bottom welds. The angle θ of the top welds may be 45degrees or greater. As with the bottom welds, the top welds may be thesame for each side of the vessel 10, or may be different, depending onthe situation.

As a consequence of this arrangement, the resulting vessel 10 whenfolded includes a side with a total length H that can be defined as anintermediate portion I plus a top length T and a bottom length B, whereB>T. When the vessel 10 is inflated, it will thus have the shapegenerally described above, with a lower portion formed by the bottomwall 12 depending from the terminus of the sidewalls 14 and a generallyplanar top wall 16.

When used in a similarly shaped support structure, such as a tank 24having an interior surface generally corresponding to the shape of thevessel 10, as shown in cross-section in FIG. 7 (and with theunderstanding that the floor of the tank 24 may include one or moreopenings for receiving drive units, tubing, port fitments, etc.), it hasbeen discovered that the tendency of the sidewalls 14 to slouch or peelaway from the corresponding walls of the tank 24 may be eliminated, orat least reduced considerably. Consequently, the incidence ofundesirable folds is likewise kept in check and a more tidy arrangementis presented. While optional, matching the contour of the floor of thetank 24 with the welds along the bottom portion of the vessel 10 mayalso help to reduce stress. The non-circular shape of the interiorcompartment also may avoid the creation of the usually undesirablevortices in the fluid that may result from agitation using a mixer orthe like, especially when located in the center of the vessel.

FIG. 8 illustrates that the bottom wall 12 of the vessel 10 may alsocomprise a rigid material 26. This may be instead of or in addition to apiece of film also forming all or a portion of the bottom wall 12, butone approach may be for the rigid material 26 to connect directly to thesidewalls 14, such as by welding (and perhaps with overlapping to helpensure the seal is formed in the desired manner). The material 26 may beformed having a polyhedral shape, such as a pyramid as described abovewith respect to the bottom wall 12 formed of the flexible film.

FIGS. 9 and 10 illustrate a further embodiment in which the rigid orflexible bottom wall 12 of the vessel 10 forms a depending portion, aswith the other embodiments described herein. In this embodiment, thecentral region 22 formed by the concurrence of the panels 12 a-12 dforming the bottom wall 12 is oversized as compared to the FIG. 4embodiment, and may take the shape of a rectangle in top plan view (FIG.10). Thus, the bottom wall 12 is formed of four generally trapezoidalpanels 12 a-12 d in this embodiment. This central region 22 may thusreceive or support any hardware, such as a drain, mixer, sparger, sensoror the like. In the case of a drain, it should be appreciated that thesloping interior surfaces of the panels 12 a-12 d help to guide thefluid toward the generally flat center of the bottom wall 12, therebyimproving efficiency and effectiveness. As should be furtherappreciated, the view of FIG. 10 could apply equally to a rigid tank forreceiving and providing support for the completely flexible vessel 10.

FIG. 11 indicates that the center region 22 may comprise, in whole or inpart, a generally flat wall, such as formed by a rigid plate 28. Thisplate 28 may also be at least partially transparent, such as forallowing light to pass for contacting an optical sensor in contact withthe fluid in the vessel, or allowing for observations, such as throughan external microscope or like device. Various ports 20 may also beprovided in the plate 28 for drains, supports for mixers, gas input, orthe like. In this embodiment, the entire bottom wall 12 may take theform of a rigid cup-shaped structure to which the film forming thesidewalls 14 is attached.

In use, the vessel 10, especially when in the form of a flexible bag, isgenerally sealed for use under sterile conditions. Any ports throughwhich additions are made to the interior compartments may includesterile connectors or filters to help ensure the sterile conditions.

The foregoing descriptions of several embodiments made according to thedisclosure of certain inventive principles are presented for purposes ofillustration and description. The embodiments described are not intendedto be exhaustive or to limit the invention to the precise form disclosedand, in fact, any combination of the components of the disclosedembodiments is contemplated. The term “flexible” as used herein in thecontext of the vessel refers to a structure of the vessel that, in theabsence of auxiliary support, may conform to the shape of the fluidcontained in the vessel, as contrasted with a “rigid” structure, whichretains a pre-determined shape when the fluid is in the vessel. Termslike “about,” generally,” and “substantially” mean that a particularitem, such as an amount, may vary slightly from a precise definition.Modifications or variations are possible in light of the aboveteachings. For example, various materials may be used to form the vesselin any combination, including polymers (such as, for example,polypropylene for any flexible portions, and high density polyethylenefor any rigid portions). The embodiments described were chosen toprovide the best illustration of the principles of the invention and itspractical application to thereby enable one of ordinary skill in the artto utilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchmodifications and variations are within the scope of the invention wheninterpreted in accordance with the breadth to which it is fairly,legally, and equitably entitled.

1. An apparatus for receiving a fluid, comprising: an at least partiallyflexible vessel including a top wall and a plurality of sidewalls, afirst of said sidewalls having a first length in a first plane that isgreater than a second length of the second, generally orthogonalsidewall in the first plane, and a bottom wall depending from the atleast two sidewalls.
 2. The apparatus of claim 1, wherein the vesselcomprises a rectangular cross-section.
 3. The apparatus of claim 1,wherein the vessel comprises a generally continuous rectangularcross-section from the top wall to the bottom wall.
 4. The apparatus ofclaim 3, wherein the area of the cross-section generally decreasescontinuously from a lowermost portion of the sidewalls to a vertex ofthe bottom wall.
 5. The apparatus of claim 1, wherein the bottom wall ofthe vessel is flexible.
 6. The apparatus of claim 1, wherein the bottomwall of the vessel is rigid.
 7. The apparatus of claim 1, wherein thebottom wall of the flexible vessel comprises at least two generallytriangular panels and at least two generally trapezoidal panels.
 8. Theapparatus of claim 1, wherein the bottom wall comprises at least fourgenerally triangular panels.
 9. The apparatus of claim 8, wherein thebottom wall comprises at least four generally trapezoidal panels. 10.The apparatus of claim 1, wherein the bottom wall comprises a centralregion including a generally flat upper surface.
 11. The apparatus ofclaim 10, wherein the central region is formed by a rigid portion. 12.The apparatus of claim 11, wherein the rigid portion includes at leastone port.
 13. The apparatus of claim 11 wherein the rigid portion is atleast partially transparent.
 14. The apparatus of claim 1, wherein thevessel includes a bottom weld for connecting at least part of the bottomwall to at least one of the sidewalls, wherein the bottom weld forms anangle of less than 45 degrees relative to the sidewall in at least afolded state.
 15. The apparatus of claim 1, wherein the vessel includesa bottom K weld that is less than 45 degrees.
 16. The apparatus of claim14, wherein the vessel includes a top K weld that is 45 degrees or more.17. (canceled)
 18. The apparatus of claim 1, wherein the vessel in afolded condition includes a side comprising a first length of a bottomportion, an intermediate portion having a second length, and a thirdlength of a top portion, wherein the first length is greater than thethird length. 19.-28. (canceled)
 29. An apparatus for receiving a fluid,comprising a vessel in the form of a bag having a top K weld, Θ, and abottom K weld, β, wherein Θ>β. 30.-39. (canceled)
 40. A method offorming a vessel for receiving a fluid, comprising: forming a dependingportion of the vessel by connecting a first panel of film adapted toform a bottom of the vessel to a second panel of film also adapted toform the bottom of the vessel at an angle of less than 45 degrees.41.-42. (canceled)
 43. The apparatus of claim 16, wherein the vesselincludes a top K weld having an angle that is greater than the angle ofthe bottom weld.